Acid neutralizing filter canister

ABSTRACT

An acid neutralizing filter construction is provided that may be used as a bypass type filter. The filter includes a canister having an open end. An end plate is secured to the canister at the open end and includes an inlet port and an outlet port to provide for fluid communication with a mounting adaptor of an oil circuit. A reactor housing is arranged inside the canister and comprises a bowl and a lid. The reactor housing defines an entrance port and an exit port. An acid neutralizing bed of acid neutralizing particles is deposited in the reactor housing. The acid neutralizing particles comprises primarily of calcium carbonate compound or other suitable medium which may be provided by crushed limestone. A particulate filter is also arranged in the reactor housing between the acid neutralizing bed and the exit port.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This patent application claims the benefit of U.S. Provisional PatentApplication No. 60/387,243, filed Jun. 7, 2002.

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for neutralizingacid in fluid circulating systems. More particularly, the invention isdirected toward an apparatus for removing acids from lubrication oil inoil circulating systems such as the oil systems associated with a dieselengine.

BACKGROUND OF THE INVENTION

Heavy duty diesel engine life, or time to rebuild, has historically beenlinked directly to piston ring, cylinder liner and/or crank shaftbearing life (referred to as “bearings” for sake of simplicity). Enginedesign parameters require that these engine components be lubricated,typically with a film lubricant of oil separating these enginecomponents to prevent or minimize direct metal to metal contact. Withoil lubricating these bearing surfaces, the principal mechanismassociated with engine wear is not metal to metal contact or frictionalwear. Instead the primary diesel engine wear component influencingengine life is corrosive wear caused by sulfur and nitrogen containingacids that are formed as products of combustion. One estimate is thatmore than 70% of heavy duty diesel engine wear is caused by suchcombustion acid metal corrosion.

Control of diesel engine corrosive wear has historically beenaccomplished through the inclusion of basic or alkaline chemicalsdissolved or suspended in the engine oil that are used to rapidlyneutralize combustion acid upon contact with the acid molecules. Therehave been proposals in the prior art to release alkaline or basicchemicals into the oil or otherwise neutralize acids utilizing a housingarranged along an oil circuit such as is disclosed in U.S. Pat. No.5,459,074 to Muoni; U.S. Pat. No. 5,718,258 to Lefebvre et al.; U.S.Pat. No. 5,068,044 to Brownawell et al.; U.S. Pat. No. 5,069,799 toBrownawell et al.; U.S. Pat. No. 5,225,081 to Brownawell et al.

Any attempt at implementing acid neutralizing technology into acommercial practical engine oil circuit needs to accommodate severalimportant factors while at the same time providing a sufficientlyinexpensive filter cartridge for maintenance intervals to make itcommercially practical for fleet managers and the like. As will beappreciated with an understanding of the present invention, these issueshave not heretofore been satisfied by the prior art.

BRIEF SUMMARY OF THE INVENTION

One aspect of the present invention is directed toward a novel acidneutralizing filter construction that may be used as a bypass typefilter. The filter includes a canister having an open end. An end plateis secured to the canister at the open end and includes an inlet portand an outlet port to provide for fluid communication with a mountingadaptor of an oil circuit. A reactor housing is arranged inside thecanister and comprises a bowl and a lid. The reactor housing defines anentrance port and an exit port. An acid neutralizing bed of acidneutralizing particles is deposited in the reactor housing. The acidneutralizing particles comprises primarily of calcium carbonate compoundwhich may be provided by crushed limestone. A particulate filter is alsoarranged in the reactor housing between the acid neutralizing bed andthe exit port. With the foregoing arrangement, a predetermined flowpassage is defined through bypass acid neutralizing filter that passesin sequence through the inlet port, the entrance port, the acidneutralizing bed, the particulate filter, the exit port and the outletport.

Another aspect of the present invention is directed toward a bypass acidneutralizing filter for an oil filtration circuit of an engine. Theintended oil filtration circuit includes an oil pump pumping oil along aprimary lubrication passage leading to engine bearings and a bypassfiltration passage arranged and restricted to pass a minority portion ofthe oil pumped by the oil pump. A full flow particulate filter isarranged upstream of the engine bearings to filter oil pumped toward theengine bearings. The bypass acid neutralizing filter configured for thisbypass circuit comprises an outer housing with an inlet port and anoutlet port that are adapted to be interposed along the bypassfiltration passage. An inner reactor housing is arranged inside theouter housing. The inner reactor housing has an entrance port and anexit port. An acid neutralizing bed of acid neutralizing particles iscontained in the inner reactor housing between the entrance port and theexit port. A bypass particulate filter is arranged in the inner reactorhousing downstream of the acid neutralizing bed. With the foregoingarrangement, a predetermined flow passage is defined through bypass acidneutralizing filter that passes in sequence through the inlet port, theentrance port, the acid neutralizing bed, the bypass particulate filter,the exit port and the outlet port. The bypass acid neutralizing filteris configured as a bypass type filter to handle less oil than thatpassed along the primary filtration path with the bypass particulatefilter being sized substantially smaller than the primary particulatefilter.

Other aspects, objectives and advantages of the invention will becomemore apparent from the following detailed description when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cutaway isometric view of an acid neutralizing bypassspin-on filter cartridge in accordance with an embodiment of the presentinvention.

FIG. 2 is an enlarged cutaway view of the bypass filter element that ismounted in the filter cartridge shown in FIG. 1.

FIG. 3 is an enlarged cutaway isometric view of the bypass filterelement arranged in an empty reactor housing for making the filtercartridge shown in FIG. 1.

FIG. 4 is an enlarged cutaway isometric view of the reactor housingshown in FIG. 3 but filled with reactant material such as crushedlimestone material which comprises primarily calcium carbonate material.

FIG. 5 is an enlarged cutaway isometric view of the reactor housingfilled with reactant and installed with a lid.

FIGS. 6 and 7 are end and cross-sectional views of the acid neutralizingbypass spin-on filter shown in FIG. 1.

FIG. 8 is a schematic representation of a full flow and bypass circuitof an engine showing the bypass filter of the present inventionincorporated thereon in accordance with an embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, an acid neutralizing bypass filter 10 is shown inaccordance with an embodiment of the present invention. The filter 10includes an outer housing and an inner reactor housing. The outerhousing is provided by a drawn metal canister 12 which includes a closeddome end 14, an open end 16 and a cylindrical side wall 18 therebetween,and an end plate 20 secured to the canister at the open end by means ofa seaming lid 22. Alternatively, the end plate 20 can be connecteddirectly to the canister without a seaming lid or via other known filtercanister/endplate manufacturing techniques. The end plate 20 includes acentral threaded outlet port 24 and a plurality of inlet ports 26 formedthrough the plate that surround the central outlet port 24. Thethreading in the outlet port 24 provides for ready spin-on connection ofthe filter 10 to an oil circuit 100 of an engine such as thatschematically shown in FIG. 8. Also as shown, an outer ring gasket 28 issupported on the outside of the outer housing and is supported by theseaming lid 22 for purposes of forming an axial seal against themounting adaptor of the engine oil circuit 100 schematically shown inFIG. 8.

As shown in the figures, the inner reactor housing is generally acontainer like structure that may be comprised of a bowl 32 and a lid34, both of which may be made of plastic material. The bowl 32 ispreferably made of a single unitary plastic injection molded body ratherthan multiple components joined together, and includes a generallycylindrical and slightly tapered outer sidewall 36 and an integrallyformed end wall 38. The sidewall 36 extends from the end wall to a freeend 40 which is configured to receive and support the lid 34. An O-ringgasket 42 is preferably positioned and arranged between the bowl 32 andthe lid 34 for preventing leakage along the free end 40.

The side wall 36 of reactor bowl 32 is concentrically disposed insidethe outer side wall 18 of the canister 12 such that a generallycylindrical flow chamber or flow passage is provided to route oil fromthe inlet ports 26 toward the dome end 14 where oil can enter thereactor housing. The reactor housing has one or more entrance ports 44and at least one exit port 46 for providing a flow path of oil throughthe reactor housing. As shown in the drawings, the entrance ports 44 arepreferably formed axially through the lid 34, but could also be formedin the bowl 32. At the other end of the reactor housing 30, the end wall38 of the reactor housing defines a centrally located exit port 46provided by a central opening formed therein. Around this exit port 46is provided an annular wall 48 on the external side of the reactorhousing 30. This annular wall 48 is connected via a radially inwardprojecting annular shoulder 50 to a generally cylindrical snout 52 thatprojects axially inside of the reactor housing 30 toward the lid 34.

An assembled generally cylindrical filter element 54 is arranged insidethe reactor housing over the snout 52 and the bowl opening or exit port46. As illustrated in FIG. 2, the filter housing comprises a cylindricaltube of filter media 56 (which may be pleated filter paper), aperforated metal center tube concentrically arranged inside of thefilter media 56, and a pair of top and bottom end caps 60, 62. Thefilter media 56 is typically potted into the end caps 60, 62. The topend cap includes a central opening that receives the cylindrical snout52 tightly therethrough for a press fit connection. An O-ring gasket 66is arranged in a formed annular retaining structure 68 on the innerperiphery of the top end cap 60 for providing a seal between the snout52 and the filter element 54 to better ensure that the acid neutralizingmedium of the reactor does not exit the reactor through the exit port 46as seen in FIG. 1.

In accordance with an aspect of the present invention, a cylindricaltube of mesh screen 70 is provided between the tube filter media 56 andcenter tube 58 to provide a further backup to the tube of filter mediato ensure that acid neutralizing particles are retained in the reactorhousing 30. The bottom end cap 62 is closed such that fluid flowing fromthe entrance ports 44 to the exit port 46 are directed and forcedthrough the cylindrical tube of filter media 56. As shown herein, thefilter element 54 preferably has an axial length that is substantiallyshorter than the axial length of the reactor housing to provide moreroom to receive acid neutralizing reactor media.

Because this filter 10 is designed as a replaceable filter cartridge ina bypass system, the filter element 54 is not designed as a full flowfilter but designed as a bypass filter with a primary function ofensuring that reactor media particles do not enter the oil circuit.Secondary functions such a fine particulate filtration can also beprovided if desired. Thus, the bypass filter element 54 is designed tobe substantially smaller than the full flow filter as will be laterdescribed with reference to FIG. 8.

With a relatively small filter element 54 being provided there is alarge amount of void space in the reactor housing (e.g. see FIGS. 3 and4) which is filled with suitable acid neutralizing media. As shownherein, the acid neutralizing media comprises primarily calciumcarbonate compound which is an extremely inexpensive compound as itoccurs naturally as limestone (limestone technically is a naturallyoccurring substance that primarily comprises calcium carbonate but mayalso include magnesium carbonate and other trace minerals or materials).Thus, the entire space of the reactor housing between the filter element54 and the bowl 32 and lid 34 is preferably filled with crushedlimestone particles 72 that provide calcium carbonate, or other suitablematerial that is sufficiently inexpensive to provide a commerciallypractical filter. As illustrated in FIG. 1, the limestone is crushed tobe fine enough to provide for a large surface area for calcium carbonatemolecules while at the same time not being too fine so as to impede orprevent flow of oil through the reactor housing 30. As oil flows throughthe reactor housing, acid molecules contained within the oil will comeinto contact with the outer surface of the limestone particles 72 andreact with calcium carbonate contained therein thereby causing areaction to take place in which the acid molecule is neutralized. Thisneutralization effectively reduces the amount of acid molecules in theoil thereby reducing wear on the bearing surfaces of the engine. Theneutralization may also prolong the maintenance service interval for anoil change.

Preferably, the reactor housing including the bowl 32 and lid 34 aremolded from plastic material to provide for relatively inexpensivemanufacture while allowing for more complex shapes to be formed. Thebowl 32 preferably includes a plurality of axially extending ribs 74 onits inner periphery arranged in an angularly spaced array about the axisthat serve to strengthen the bowl 32, and also provide a means forcentering the filter element 54 over the snout when it is insertedduring assembly, and for also providing a stop shoulder for the lid 34at the free end 40.

A further feature achieved through molding is that fine mesh material 76is preferably molded directly into and over the reactor entrance ports44 as illustrated in FIG. 5. In this manner, the crushed limestoneparticles 74 is retained within the reactor housing and not allowed toenter the outer canister 12. The fine mesh material 76 is finer than thesize of the crushed limestone particles 72. This provides the featurethat when oil is not flowing through the acid neutralizing bypass filter10, limestone particles do not somehow migrate into the oil fluidcircuit by backing up through the external inlet ports 26 of the bypassfilter 10.

The exit port 46 of the reactor housing 30 is connected to the outletport 24 of the outer housing via a cylindrical adaptor seal 78 extendingtherebetween. The adaptor seal 78 is received into the opening or exitport 46 of the bowl 32 and is concentrically arranged within the annularwall 48. The adaptor seal 78 preferably includes an outwardly projectingannular flange that is acted upon by higher pressure on the inlet sideof the filter and is thereby pressed into sealing engagement against theend wall 38 of the bowl 32 to prevent leakage therebetween. The adaptorseal also includes an annular sealing edge 82 that is received into anannular pocket 84 that is formed integrally into the underside of theouter end plate 20. A coil spring 86 supported by the closed dome end 14of the outer canister 12 engages the lid 34 to maintain the lid 34axially against the reactor bowl 32 and also urges the adaptor seal 82against the end plate 20 such that an axial seal is formed between theend plate 22 and the annular sealing edge 82 of the adaptor seal 78. Thecylindrical adaptor seal 78 includes a central passage 88 that directlyconnects the exit port 46 to the external outlet port 24.

As noted above, a preferred embodiment of the present invention is inthe form of a bypass filter 10 for an engine oil circuit 100 which isschematically indicated in FIG. 8. This oil circuit 100 includes an oilpump 102 that pumps oil along a passage first through a full flow filter104 that passes oil pumped by oil pump 102. Thereafter, there is a splitin the circuit and the oil can either pass through the bypass line 106or a primary oil line 108. With all of the oil that is jetted toward thebearings 110 through the primary oil line 108 passing through the fullflow particulate filter 104, undesirable particulates (sized greaterthan the porosity of the full flow filter) are removed by the full flowparticulate filter 104 prior to reaching the bearings 110, hence theterm “full flow” (the bearings 110 represent and are meant to includethe metal to metal sliding surfaces as is described in the backgroundsection). During engine operation it is critical to have the bearingsurfaces 110 continuously lubricated via oil to provide a thin film thateffectively substantially prevents metal to metal contact therebypreventing wear. Therefore, substantially all of the oil passing throughthe full flow particulate filter is routed through the primary oil line108 and through the bearings 110 where thereafter eventually returns tothe oil pan or sump 112. However, a small portion of the oil is routedalong the bypass line 106 and passed through the bypass filter 10 of thepresent invention. A restriction orifice 114 which may be roughly about0.105″ in diameter strictly limits the amount of oil passing along thebypass line 106. During regular operation, about 10% of the total flowpassing through the full flow filter 104 (but it may be designed to beanywhere between roughly 5% and 20% for normal engine operation).Importantly, not too much oil is passed through the bypass line 106otherwise, when oil pressure drops when the engine is idling,insufficient pressure may not be available to supply sufficient oil tothe bearings 1 10 of the engine. This is because the restriction orifice114 stays the same despite less oil being pumped.

Also a critical aspect of the present invention is that not all oilpumped by the oil pump 102 is passed through the bed of limestoneparticles 72 by virtue of the bypass filter cartridge 10 being mountedin the bypass line 106 rather than the primary oil line 108 or where thefull flow particulate filter 104 is located. The importance of this isthat there is the possibility that the relatively fine crushed particlesize of the limestone particles 72 could become clogged either throughcompaction, sludge forming and being retained within the limestoneparticle bed, a combination of these factors or otherwise. Simply put,the inventors of the present invention have determined that it is toomuch of a risk to consider placing the limestone bed along the full flowfilter path as there would be an increase potential for plugging the oilcircuit and thereby preventing the critical oil flow to the bearings110. By placing the bed of crushed limestone particles 72 on the bypassline, the limestone particles can be crushed to be significantly smallerand thereby provide much more acid reacting surface area than couldotherwise be obtained along the primary flow path to the bearings 110.As a result, the way the invention has been incorporated, the acidscontained in the oil are systematically removed by a small portion ofthe oil containing such acids passing through the bypass line and bypassfilter thereby reducing corrosion and wear of metal components. At thesame time, by placing the bypass filter in parallel circuit with thebearings 10, there is not a chance that oil flow to the bearings will beplugged by virtue of the bed of relatively finely crushed limestoneparticles 72.

A further advantage of the present invention is that the bypass filtercartridge 10 can be made in a very economical fashion since thecomponents to the bypass filter are made using in part conventionalfilter manufacturing technologies, very inexpensive acid neutralizingmedia which occurs naturally (e.g. limestone) which is anticipated tocost only a couple cents per filter at most, an extremely small bypassfilter element that can also be inexpensive as a result of its verysmall size needed only to ensure that particles of limestone material donot enter the fluid circuit. The bypass filter element 54 can be sizedto be substantially smaller and configured to pass substantially lessoil than the full flow filter 104 which is schematically illustrated inFIG. 8. This also keeps the cost of the filter cartridge 10 to besufficiently inexpensive to make it practical and economically forcommercial applications while achieving acid neutralization and extendedservice intervals and/or reduced corrosive wear and extended enginelife.

The method of manufacturing the present invention also provides a verycost effective way to manufacture the disclosed bypass filter 10 to makeit commercially practical. Accordingly, the assembly of the filter 10starts with the assembly of the small bypass filter element 54 as shownin FIG. 2. The tube of filter media 56 and a meshed lined center tube 58are potted into open and closed end caps 60, 62 (although a partiallength media tube 56 is shown, the figure bypass element 54 could alsobe a full length tube extending the axial length of the reactorhousing). The tube of filter media 56 may be pleated cellulose filterpaper, depth filtration tube media, or other suitable filtration media.The bypass element 54 is then assembled into the reactor housing 30 withthe O-ring seal gasket 66. The reactor housing 30 includes the hollowsnout 52 on the internal side of the housing to mate and seal with thefilter bypass element 54. The open end cap 60 has an inside diameterthat is slightly smaller than the mating snout in the reactor housing 30that provides for a press fit connection. Other methods to retain theelement could also be used including potting and/or glue or bindermaterial or other mechanical retainer mechanism. The reactor housing 30is then ready to be filled with the reactant which in this case isprimarily calcium carbonate as provided by crushed limestone particles72. The calcium carbonate is filled and compacted into the reactorhousing 30. A plastic lid 34 is then installed as shown in FIG. 5. Thelid 34 is snapped inside the bowl 32 of the reactor housing and anO-ring located in an O-ring groove on the lid 34 provides a seal.

The remaining spin-on canister 12 is assembled as any ordinary spin-onlube filter with the reactor replacing the filter element. This assemblystarts with a base plate 20 which has a seaming lid 22 welded to it. Theadaptor seal 78 is placed on the base plate 20 followed with theassembled reactor housing 30. A spring is set in the spring pocket 90defined by the lid 34 and the formed canister 12 is placed over thespring 86. The canister 12 and seaming lid 22 are then double seamedtogether to secure the end plate 20 to the outer housing. Finally, theouter gasket 28 is installed in the seaming lid 22.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention.Variations of those preferred embodiments may become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Theinventors expect skilled artisans to employ such variations asappropriate, and the inventors intend for the invention to be practicedotherwise than as specifically described herein. Accordingly, thisinvention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

1. An acid neutralizing filter, comprising: a canister having an openend; an end plate secured to the canister at the open end, the end platehaving an inlet port and an outlet port; a reactor housing arrangedinside the canister, the reactor housing comprising a bowl and a lid,the reactor housing comprising an entrance port and an exit port; anacid neutralizing bed of acid neutralizing particles in the reactorhousing, the acid neutralizing particles comprising primarily of calciumcarbonate; a particulate filter in the reactor housing between the acidneutralizing bed and the exit port; and a predetermined flow passagethrough the bypass acid neutralizing filter passing in sequence throughthe inlet port, the entrance port, the acid neutralizing bed, theparticulate filter, the exit port and the outlet port.
 2. The acidneutralizing filter of claim 1, wherein the bowl includes an end walland a tubular sidewall, the sidewall having a plurality of ribs thatextend axially and that are angularly spaced.
 3. The acid neutralizingfilter of claim 2 wherein the particulate filter comprises a tubularfilter media contained between end caps, and wherein the particulatefilter is concentrically arranged inside of the ribs.
 4. The acidneutralizing filter of claim 1, wherein the bowl includes an end walland a tubular sidewall extending axially therefrom, the end wall havinga central opening providing said exit port and communicating with theoutlet port.
 5. The acid neutralizing filter of claim 4, wherein thebowl defines an annular wall surrounding the central opening, furthercomprising an annular adaptor seal member extending into the centralopening.
 6. The acid neutralizing filter of claim 5, wherein the annularseal member includes a radially outward flange engaging the end wall ofthe bowl and an annular tip engaging the end plate, further comprising aspring supported by the canister biasing the bowl toward the endplateand thereby compressing the seal member between the bowl and the endplate.
 7. The acid neutralizing filter of claim 1, wherein the bowl andthe lid of the reactor housing are molded from plastic material.
 8. Theacid neutralizing filter of claim 7, further comprising mesh materialmolded into the reactor housing over the entrance port for retainingparticles of the acid neutralizing bed in the reactor housing.
 9. Theacid neutralizing filter of claim 1, wherein the particulate filtercomprises a tube of filter media, first and second end caps secured toopposing ends of the tube of filter media, a perforated center tubeconcentrically arranged inside of the tube of filter media and acylindrical ring of mesh material between the tube of filter media andthe perforated center tube.
 10. The acid neutralizing filter of claim 9,wherein the first end cap has a central opening communicating with theexit port through the bowl and the second end cap is closed, and whereinthe particular filter has an axially length that is substantiallyshorter than the reactor housing, such that the second end cap is spacedaxially from the lid with acid neutralizing particles containedtherebetween.
 11. The acid neutralizing filter of claim 10, wherein thereactor housing defines said entrance and said exit port proximateopposed axial ends of the reactor housing, wherein oil flow through thereactor housing is imparted with substantial axial and radial travelcomponents.
 12. The acid neutralizing filter of claim 10, wherein thebowl integrally includes an annular snout projecting inside of the bowland through the first end cap has a central opening.
 13. The acidneutralizing filter of claim 1, wherein the bowl includes an end walland a tubular sidewall terminating in a free end, the lid engaging thefree end, and wherein the end wall defines a central opening providingsaid exit port communicating with the outlet port, and wherein the liddefines a plurality of said entrance ports, the reactor housing beingarranged such that oil flows, in sequence, through the inlet port downan annular space defined between the reactor housing and the canister toa closed end dome portion of the canister, axially through entranceports defined by the lid, axially and radially through the acidneutralizing bed, through the particular filter and then through theexit and outlet ports.
 14. The acid neutralizing filter of claim 1,wherein the acid neutralizing particles consist essentially of crushedlimestone particles. 15-25. (canceled)